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Either of you find a solution? Having same problem with 97 Rodeo. Started right after replacing a bad alternator. Had new alt. tested. It's good. Battery is good. Tested wiring and everything checks out. Only thing I can't test is the ECM. Don't have Check Engine Light on or any other lights other than the Battery/Charge light on.

I just went through this problem. I found out that the regulator was bad in the alternator. This was after I had taken the rodeo back to the auto parts store and had it checked. Then I was not satisfied so I took the alternator off and took it to have it check, An both times it show it was charging.The people at the auto store said I may have broke a wire when I took it out. By this time I had check all of the fuses,relays and rechecked the wires. I had called a auto electrical place and a Isuzu dealer and the auto elect. got his hot line and found out that a lot of peole had the same problem and 95% were the alternator.So today I took the alternator off again and took it back and I talked to a different sales person and was telling him what I had found out. An the first words out of him was that regulator was bad. I wish he had been there two weeks a go.So know the heating and air conditioner our working and the dash lights or off and the amp hand is working. I am sorry to tell you at first that this was 1996 redeo. I hope this helps. mcdon

Thanks for the reply. Ended up going to a mechanic who said what I suspected - alternator is bad. I had done all the things you did. I checked fuses, relays, etc. prior to taking it to a mechanic Guys at the parts house reluctantly replaced the alternator yesterday (after I spoke to a manager). One guy was asking if they checked the fusible link (trick question). Told him they and I checked the fuses and relay for the ECM, etc. and that shut him up. Anyway, new alternator works fine which means the regulator was bad (just like you mentioned) in the old new alternator.

I was driving along happy in my 97 Rodeo, when all of the sudden, my A/C and fan motor went dead, and my brake, battery, and 4WD indicator lights came on. I checked fuses, and immediately suspected an alternator issue, and got a replacement from Advance. I replaced the unit, but no change. I checked fuses again, and switched relays around, nothing worked. When I took the core back, I had them test it, and they said it was only putting out 10 volts. I took the new one in and had it tested, and it was OK. I took it to the dealer, and they said that the aftermarket alternators aren't any good. I new OEM was around $500. I went to NAPA, and picked up another and put it in, again nothing. I noticed that unplugging one of the harnesses to the alternator enabled my A/C to run. Further playing around, I found that there is a Red wire with a white stripe that leaves one of the two alternator harness connectors by the engine fuse box. Once I disconnected that wire from the harness connector ( it comes apart ) my alternator is charging, and everything is back to normal. This wire connects the alternator to the computer, and I believe serves some enabling function. When I connect even my digital volt meter to the alternator on that pin, it cuts the alternator output. When they tested the alternator at the store, they basically hook up 3 wires: ground, 12 in, 12 out. The wiring harnesses provide like 5 paths plus the chasis ground. I will eventually get the OEM alternator replaced to verify, But in a pinch, I hope this helps. I just think there's an Isuzu specific circuit that isn't verified by the re-manufacturers, and that's why 95% of these don't work.On the plus side, I've had the alternator out so many times I can replace it in about 15 minutes while the engine is still hot :P

The problem is all the same as everybody else.Its not the regulator that is inside the alternator.The problem is the Harmonic Balancer went bad so its slipping so the belt turns slower than normal given you all this problem.Hope this helps .

Thank you so much for taking the time to write that. I had the same thing happen to me 100% the same with the indicator lights and everything. I'm not sure the cause of this problem,but disconnecting the wire harness worked for me. Saved me a ton of time and money. Again thanks for your input.

My 2004 Rodeo sat for a few months before I bought it. The batter would not hold a charge. Once I was 'jumped' I could drive with no problem. I took my Rodeo for an oil change; then my 'check engine,' 'ABS' and 'check 4wd' came on. Any ideas what the problem might be? I also put in a new battery too. Thank you.

After reading previous post, I cut the red/white wire near the plug and ran wire from plug to battery positive post, pretty much bypassing alternator, and it still tells ECU whats going on with charging. All systems back to normal, from dash lights, and AC all working correctly. Thanks mwolfe for bringing this to our attention. This post really helped me with solving these issues.

I have a 1998 Isuzu rodeo & everything was working fine until I tried turning it back on it wouldn't start anymore ..they battery is fine but it won't start for some reason ..can someone help me out here .